Is It Possible for Our Genes to Learn?
Life events (e.g., stress) alter how our genes behave. But can they also learn?
Posted Mar 05, 2021 | Reviewed by Devon Frye
- Genes were once thought to be static. But recent research in the field of epigenetics has found that genes can and do change in response to environmental cues.
- We know that genes are capable of changing their behavior.
- But whether genes can habituate themselves to repeated environmental cues—which can be described as learning—is less well-understood.
- Scientists are studying whether genes can learn—and their upcoming research may upend the current understanding of nature vs. nurture.
Over the past decade, research has transformed our understanding of genetic material. The "classical" perspective outlined in our high-school textbooks suggested that genes are "static" pieces of biological code that blindly spit out proteins, unaffected by the world around them.
However, it turns out that the very opposite is true: events that occur during our lives, and perhaps even the lives of our parents and grandparents, can trigger profound and long-lasting changes at the genetic level. From womb to tomb, our genes dynamically react to the world around them.
Simply put, our genetic material can behave. But can it also learn? And if so, how exactly do we know when "genetic learning" has taken place?
What Is Learning?
Answering these questions requires that we first take a step back, and figure out what we mean by behavior, changes in behavior, and learning. When we use the term "behavior," we are referring to a transition from one state to another that’s due to a stimulus. Sounds complicated, right? So let’s take a simple example. Imagine you’re sitting in your front garden, and the exhaust of your neighbor’s car backfires every day as he drives to work. The first time you (i.e., the system) hear this loud bang (i.e., a stimulus) you go from being calm to highly startled (i.e., a transition in state). Thus when we say something or someone is behaving, we are actually describing a transition between one state and another (from being calm to startled), and are explaining why this transition has occurred (because of a loud bang).
Now many systems (especially living ones) don’t just behave. They also change their behavior. Imagine that it’s several days later and you’re back in your front garden. Your neighbor’s troublesome car once again backfires as he drives by. But this time, you’re only slightly startled by the sound. When we say that your behavior has changed, we are simply pointing out that there is a difference in how the same stimulus (the loud bang) initially affected you (you originally went from calm to highly startled) compared to its impact several days later (you now go from calm to only slightly startled).
Now for the real question: Why did your behavior change? Why does the loud bang no longer startle you the way it once did?
This brings us to learning. When we refer to learning, we are highlighting that a change in behavior has occurred and are explaining why that change has taken place. For instance, our behavior may change because we’ve encountered a single stimulus over and over again. In our earlier example, the repeated backfiring of your neighbor’s car every day may lead you to no longer be startled, and even ignore the loud bang altogether; this is known as habituation.
Behavior may also change because stimuli have been paired together. Remember Pavlov’s dog? He initially didn’t salivate when a bell was rung. But after the bell was paired with food, the dog started to salivate as soon as the bell was rung; this is known as classical conditioning. Finally, our behavior may change because it leads to certain outcomes. Dog trainers, for example, often reinforce "good" behaviors like sitting and staying quiet with access to desired outcomes such as dog treats; this is known as operant conditioning.
What is Genetic Learning?
It turns out that most living creatures learn. But what about neurons, cell assemblies, or even genetic material (i.e., parts of living creatures)? Can they also behave? Change their behavior? And possibly learn?
Take genetic material. It turns out that some of our genes (system) are switched on (transition in state) in the morning when we are exposed to sunlight (stimulus)—i.e., they behave. Later in the evening, when the sun goes down (stimulus), those same genes (system) are switched off—i.e., they are capable of changing their behavior. In this way, the rhythms of our gene expression are synchronized to the rhythms of the natural world, allowing us to adapt to the environments we find ourselves in (e.g., use energy during the day when we need it and conserve it at night).
Now for the real question: Can those same genes also learn? For instance, if a person was repeatedly exposed to pulses of light during the night, would these genes initially be expressed and then slowly stop being expressed (i.e., would they habituate, as you did to the loud bang of your neighbor’s car)? If we paired light with a certain sound, and then presented that sound to a person in the dark, would their genes start to be expressed (just as Pavlov’s dog salivated when he heard the bell)? Finally, imagine that a person was starving, and expressing those genes led to the delivery of food. Would gene expression increase at all?
Work on genetic learning has only just begun. But there are strong hints that genetic material is indeed capable of learning. If so, then many interesting questions are waiting to be answered. For instance, does genetic learning about one stimulus (a loud bang) generalize to other stimuli (a loud scream)? If problematic experiences such as childhood trauma, abuse, malnutrition, or stress lead to maladaptive changes in genetic behavior, can these be later undone? Are there certain windows of time where genes can learn, and does genetic learning persist? Perhaps most interesting, can what genetic material learns in one generation be passed down and inherited by others?
Science tells us that our genes are capable of behaving and changing their behavior. Asking if they can also learn unlocks many new ideas and possibilities. If they can, then our understanding of activity on the smallest of scales would be further transformed, and suggest that our genes are dynamically sensitive to the world around them (rather than being the static entities once assumed). It may be that nature and nurture have long been locked in a conversation that we are only now starting to understand.
The author wishes to thank Jan De Houwer for feedback on an earlier version.
This post is inspired by a scientific paper ("Genetic Learning: A New Conceptual Framework for Studying the Impact of the Environment on Changes in Genetic Behavior") of ours ( Hughes, S., Soubry, A., & De Houwer, J. ) that is currently under review at BioEssays.
Carey, N. (2012). The Epigenetics Revolution: How Modern Biology is Rewriting Our Understanding of Genetics, Disease, and Inheritance. Columbia University Press, New York, NY.
De Houwer, J., & Hughes, S. (2020). The Psychology of Learning: An Introduction from a Functional-Cognitive Perspective. The MIT Press.
Hughes, S., Soubry, A., & De Houwer, J. (under review). Genetic Learning: A New Conceptual Framework for Studying the Impact of the Environment on Changes in Genetic Behavior. BioEssays.
Moore, D. S. (2015). The Developing Genome: An Introduction to Behavioral Epigenetics. Oxford University Press, New York, NY.